Moloy Das

Efficacy of Catheter Ablation for Persistent Atrial Fibrillation A Systematic Review and Meta-Analysis of Evidence From Randomized and Nonrandomized Controlled Trials

Background—Catheter ablation (CA) is commonly performed for persistent atrial fibrillation, but few high-quality randomized controlled trials (RCTs) exist, leading to funding restrictions being proposed in several countries. We performed a random-effects meta-analysis of RCTs and non-RCTs to assess the efficacy of CA for persistent atrial fibrillation. Methods and Results—We systematically searched PubMed, EMBASE, CENTRAL, OpenGrey, and clinicaltrials.gov for RCTs and non-RCTs reporting clinical outcomes after CA for persistent atrial fibrillation. Forty-six eligible studies were identified containing 3819 patients. After a single procedure, CA significantly reduced the risk of recurrent atrial fibrillation compared with medical therapy (odds ratio [OR], 0.32; 95% confidence interval [CI], 0.20–0.53; P<0.001). Outcomes were better if the pulmonary veins were encircled (OR, 0.26; 95% CI, 0.09–0.74; P=0.01), and electrical isolation reduced AF recurrence compared with purely anatomic encirclement (OR, 0.33; 95% CI, 0.13–0.86; P=0.02). Linear ablation within the left atrium (OR, 0.22; 95% CI, 0.10–0.49; P<0.001), but not complex fractionated atrial electrogram ablation (OR, 0.64; 95% CI, 0.35–1.18; P=0.15), significantly reduced AF recurrence. Results were not improved by performing more extensive linear lesion sets (OR, 0.77; 95% CI, 0.41–1.43; P=0.40) or from biatrial ablation (OR, 0.62; 95% CI, 0.31–1.24; P=0.17). Where data were available, the relative benefits seen held true both after a single or multiple procedure(s). Sensitivity analyses showed that inclusion of non-RCTs increased statistical power without biasing the calculated effect sizes. Conclusions—For patients with persistent atrial fibrillation, CA achieves significantly greater freedom from recurrent atrial fibrillation compared with medical therapy. The most efficacious strategy is likely to combine isolation of the pulmonary veins with limited linear ablation within the left atrium.Background— Catheter ablation (CA) is commonly performed for persistent atrial fibrillation, but few high-quality randomized controlled trials (RCTs) exist, leading to funding restrictions being proposed in several countries. We performed a random-effects meta-analysis of RCTs and non-RCTs to assess the efficacy of CA for persistent atrial fibrillation. Methods and Results— We systematically searched PubMed, EMBASE, CENTRAL, OpenGrey, and [clinicaltrials.gov][1] for RCTs and non-RCTs reporting clinical outcomes after CA for persistent atrial fibrillation. Forty-six eligible studies were identified containing 3819 patients. After a single procedure, CA significantly reduced the risk of recurrent atrial fibrillation compared with medical therapy (odds ratio [OR], 0.32; 95% confidence interval [CI], 0.20–0.53; P <0.001). Outcomes were better if the pulmonary veins were encircled (OR, 0.26; 95% CI, 0.09–0.74; P =0.01), and electrical isolation reduced AF recurrence compared with purely anatomic encirclement (OR, 0.33; 95% CI, 0.13–0.86; P =0.02). Linear ablation within the left atrium (OR, 0.22; 95% CI, 0.10–0.49; P <0.001), but not complex fractionated atrial electrogram ablation (OR, 0.64; 95% CI, 0.35–1.18; P =0.15), significantly reduced AF recurrence. Results were not improved by performing more extensive linear lesion sets (OR, 0.77; 95% CI, 0.41–1.43; P =0.40) or from biatrial ablation (OR, 0.62; 95% CI, 0.31–1.24; P =0.17). Where data were available, the relative benefits seen held true both after a single or multiple procedure(s). Sensitivity analyses showed that inclusion of non-RCTs increased statistical power without biasing the calculated effect sizes. Conclusions— For patients with persistent atrial fibrillation, CA achieves significantly greater freedom from recurrent atrial fibrillation compared with medical therapy. The most efficacious strategy is likely to combine isolation of the pulmonary veins with limited linear ablation within the left atrium. [1]: http://clinicaltrials.gov

Relationship between contact force sensing technology and medium-term outcome of atrial fibrillation ablation: a multicenter study of 600 patients.

Contact force sensing (CFS) technology improves acute pulmonary vein isolation durability; however, its impact on the clinical outcome of ablating atrial fibrillation (AF) is unknown.

Ablation index, a novel marker of ablation lesion quality: prediction of pulmonary vein reconnection at repeat electrophysiology study and regional differences in target values

Aims Force-Time Integral (FTI) is commonly used as a marker of ablation lesion quality during pulmonary vein isolation (PVI), but does not incorporate power. Ablation Index (AI) is a novel lesion quality marker that utilizes contact force, time, and power in a weighted formula. Furthermore, only a single FTI target value has been suggested despite regional variation in left atrial wall thickness. We aimed to study AIs and FTIs relationships with PV reconnection at repeat electrophysiology study, and regional threshold values that predicted no reconnection. Methods and results Forty paroxysmal atrial fibrillation patients underwent contact force-guided PVI, and the minimum and mean AI and FTI values for each segment were identified according to a 12-segment model. All patients underwent repeat electrophysiology study at 2 months, regardless of symptoms, to identify sites of PV reconnection. Late PV reconnection was seen in 53 (11%) segments in 25 (62%) patients. Reconnected segments had significantly lower minimum AI [308 (252-336) vs. 373 (323-423), P < 0.0001] and FTI [137 (92-182) vs. 228 (157-334), P < 0.0001] compared with non-reconnected segments. Minimum AI and FTI were both independently predictive, but AI had a smaller P value. Higher minimum AI and FTI values were required to avoid reconnection in anterior/roof segments than for posterior/inferior segments (P < 0.0001). No reconnection was seen where the minimum AI value was ≥370 for posterior/inferior segments and ≥480 for anterior/roof segments. Conclusion The minimum AI value in a PVI segment is independently predictive of reconnection of that segment at repeat electrophysiology study. Higher AI and FTI values are required for anterior/roof segments than for posterior/inferior segments to prevent reconnection.

Recurrence of Atrial Tachyarrhythmia During the Second Month of the Blanking Period Is Associated With More Extensive Pulmonary Vein Reconnection at Repeat Electrophysiology Study

Background—Current guidelines recommend a 3-month blanking period after pulmonary vein isolation (PVI) as early recurrence of atrial tachyarrhythmia (ERAT) may be due to transient proarrhythmic factors. However, studies have suggested that these factors resolve by 1 month. PV reconnection (PVrc) is strongly associated with postblanking AT recurrence in paroxysmal atrial fibrillation. We hypothesized that ERAT occurring beyond 4 weeks after PVI is associated with PVrc at repeat electrophysiology study. Methods and Results—Forty patients with paroxysmal atrial fibrillation underwent mandatory repeat electrophysiology study 2 months after PVI, regardless of symptoms, to document the number of reconnected PVs. Antiarrhythmic drugs, including &bgr;-blockers, were discontinued 4 weeks after PVI. Patients were instructed to record a 30-second ECG everyday between the 2 procedures using a portable monitor, with additional recordings for symptoms. ERAT was defined as ≥30 seconds of AT. Patients recorded a total of 3293 ECGs. Four (10%) patients had ERAT in the first 4 weeks (M1) only, 2 (5%) in month 2 (M2) only, and 11 (28%) in both. PVrc of 1 PV was identified in 12 (30%) patients and of >1 PV in 13 (32%) patients. ERAT in M2 was associated with PVrc, whereas M1 was not (11/13 [85%] versus 0/4 [0%]; P=0.006). M2 ERAT was strongly associated with PVrc of >1 PV (10/13 [77%] versus 3/27 [11%] without M2 ERAT; P<0.0001). Conclusions—ERAT occurring beyond 4 weeks after PVI is associated with PVrc and particularly of PVrc of >1 PV. ERAT confined to M1 is unrelated to underlying PVrc. The relationship between ERAT beyond 4 weeks after PVI and postblanking AT recurrence merits further investigation.

Prospective use of Ablation Index targets improves clinical outcomes following ablation for atrial fibrillation

Late recovery of ablated tissue leading to reconnection of pulmonary veins remains common following radiofrequency catheter ablation for AF. Ablation Index (AI), a novel ablation quality marker, incorporates contact force (CF), time, and power in a weighted formula. We hypothesized that prospective use of our previously published derived AI targets would result in better outcomes when compared to CF‐guided ablation.

Reablated Sites of Acute Reconnection After Pulmonary Vein Isolation Do Not Predict Sites of Late Reconnection at Repeat Electrophysiology Study

Acute reconnection of pulmonary veins (PVs) is frequently seen in the waiting period following pulmonary vein isolation (PVI). There are concerns that reablation at these sites may not be durably effective due to tissue edema caused by the initial ablation. We aimed to prospectively study the relationship between acute and late reconnection.

Primary Care Atrial Fibrillation Service: outcomes from consultant-led anticoagulation assessment clinics in the primary care setting in the UK.

Objective Stroke-risk in atrial fibrillation (AF) can be significantly reduced by appropriate thromboembolic prophylaxis. However, National Institute for Health and Care Excellence estimates suggest that up to half of eligible patients with AF are not anticoagulated, with severe consequences for stroke prevention. We aimed to determine the outcome of an innovative Primary Care AF (PCAF) service on anticoagulation uptake in a cohort of high-risk patients with AF in the UK. Methods The PCAF service is a novel cooperative pathway providing specialist resources within general practitioner (GP) practices. It utilises a four-phase protocol to identify high-risk patients with AF (CHA2DS2-VASc ≥1) who are suboptimally anticoagulated, and delivers Consultant-led anticoagulation assessment within the local GP practice. We assessed rates of anticoagulation in high-risk patients before and after PCAF service intervention, and determined compliance with newly-initiated anticoagulation at follow-up. Results The PCAF service was delivered in 56 GP practices (population 386 624; AF prevalence 2.1%) between June 2012 and June 2014. 1579 high-risk patients with AF with suboptimal anticoagulation (either not taking any anticoagulation or taking warfarin but with a low time-in-therapeutic-range) were invited for review, with 86% attending. Of 1063 eligible patients on no anticoagulation, 1020 (96%) agreed to start warfarin (459 (43%)) or a non-vitamin K antagonist oral anticoagulant (NOAC, 561 (53%)). The overall proportion of eligible patients receiving anticoagulation improved from 77% to 95% (p<0.0001). Additionally, 111/121 (92%) patients suboptimally treated with warfarin agreed to switch to a NOAC. Audit of eight practices after 195 (185–606) days showed that 90% of patients started on a new anticoagulant therapy had continued treatment. Based on data extrapolated from previous studies, around 30–35 strokes per year may have been prevented in these previously under-treated high-risk patients. Conclusions Systematic identification of patients with AF with high stroke-risk and consultation in PCAF consultant-led clinics effectively delivers oral anticoagulation to high-risk patients with AF in the community.

Accuracy of left atrial bipolar voltages obtained by ConfiDENSE multielectrode mapping in patients with persistent atrial fibrillation

The ConfiDENSE™ module (Carto3 v4) allows rapid annotation of endocardial electrograms acquired by multielectrode (ME) mapping. However, its accuracy in assessing atrial voltages is unknown.

A Novel Marker to Predict Early Recurrence After Atrial Fibrillation Ablation: The Ablation Effectiveness Quotient

Inability to predict clinical outcome despite acutely successful pulmonary vein isolation (PVI) remains the Achilles’ heel of atrial fibrillation ablation (AFA). Arrhythmia recurrence is frequently due to recovery of radiofrequency (RF) ablation lesions believed to be complete at the original procedure.

Automated Quantification of Low-Amplitude Abnormal QRS Peaks From High-Resolution ECG Recordings Predicts Arrhythmic Events in Patients With Cardiomyopathy

Background— Cardiomyopathy patients are at risk of sudden death, typically from scar-related abnormalities of electrical activation that promote ventricular tachyarrhythmias. Abnormal intra-QRS peaks may provide a measure of altered activation. We hypothesized that quantification of such QRS peaks (QRSp) in high-resolution ECGs would predict arrhythmic events in implantable cardioverter–defibrillator (ICD)–eligible cardiomyopathy patients. Methods and Results— Ninety-nine patients with ischemic or non-ischemic dilated cardiomyopathy undergoing prophylactic ICD implantation were prospectively enrolled (age 62±11 years, left ventricular ejection fraction 27±7%). High-resolution (1024 Hz) digital 12-lead ECGs were recorded during intrinsic rhythm. QRSp was quantified for each precordial lead as the total number of low-amplitude deflections that deviated from their respective naive QRS template. The primary end point of arrhythmic events was defined as appropriate ICD therapy or sustained ventricular tachyarrhythmias. After a median follow-up of 24 (15–43) months, 20 (20%) patients had arrhythmic events. Both QRSp and QRS duration were greater in those with arrhythmic events (both P<0.001) and this was consistent for QRSp for both cardiomyopathy types. In a multivariable Cox regression model that included age, left ventricular ejection fraction, QRS duration, and QRSp, only QRSp was an independent predictor of arrhythmic events (hazard ratio, 2.1; P<0.001). Receiver operating characteristic analysis revealed that a QRSp ≥2.25 identified arrhythmic events with greater sensitivity (100% versus 70%, P<0.05) and negative predictive value (100% versus 89%, P<0.05) than QRS duration ≥120 ms. Conclusions— QRSp measured from high-resolution digital 12-lead ECGs independently predicts ventricular tachyarrhythmias in ICD-eligible cardiomyopathy patients. This novel QRS morphology index has the potential to improve sudden death risk stratification and patient selection for prophylactic ICD therapy.